The present invention relates to a solenoid valve. Specifically, the present invention relates to a hydraulic solenoid valve to be used in an anti-lock brake system for vehicles.
Japanese Laid-Open Utility Model Publication No. HEI 2-34875 refers to a solenoid valve. This prior art consists of a bobbin with a wound coil disposed in a valve housing having a valve seat at the bottom, a movable pole piece having a valve member at the end face therein, and a spring which biases the movable pole piece in a seal pipe. A closure is placed at the open end of the valve housing.
The disadvantage of the prior art is that the solenoid valve is difficult to assemble. For example, two steps are required to assemble the seal pipe and insert it in the valve housing. First, a fixed core (or vane stopper), which is mounted on the cover, must be pressed onto one end of the seal pipe. Second, the other end of the seal pipe is pressed into an engaging hole at the lower part of the valve housing.
Because two pressing steps are required to set both ends of the seal pipe, the solenoid valve takes longer to assemble, thereby increasing production and manufacturing costs.
Attaching the closure to one end of the seal pipe is difficult in the prior art, because the movable pole piece easily falls out of the other open end when the valve housing is being set. Therefore, additional steps are required while assembling the valve in order to keep the movable pole piece from falling out.